JP2019508520A - Cleaning composition for liquid crystal alignment film and method for producing liquid crystal alignment film using the same - Google Patents

Abstract

The present invention relates to a cleaning composition for a liquid crystal alignment film, a method of manufacturing a liquid crystal alignment film using the same, and a liquid crystal display device including the liquid crystal alignment film manufactured by the above method. More specifically, after the UV alignment process, the non-uniform problem of the liquid crystal alignment film is solved by using a cleaning composition containing a specific solvent in the cleaning process, and the ionic by-products on the polymer surface are effectively removed. Thus, a cleaning composition for a liquid crystal alignment film capable of enhancing the anisotropy of the liquid crystal alignment film and a method for producing the liquid crystal alignment film are provided.

Description

This application claims the benefit of priority based on Korean Patent Application No. 10-2016-0025873, filed March 3, 2016, the entire contents of which are disclosed in the documents of the Korean patent application. It is incorporated as part of the present specification.

  The present invention is directed to a liquid crystal alignment film capable of enhancing the anisotropy of the liquid crystal alignment film in the process of manufacturing a liquid crystal alignment film formed using a liquid crystal alignment agent, and suppressing the problem of nonuniformity generated in the processing process. The present invention relates to a cleaning composition, a method of manufacturing a liquid crystal alignment film including a cleaning method using the same, and a liquid crystal display device including the liquid crystal alignment film manufactured by the above method.

  In the liquid crystal display element, the liquid crystal alignment film plays a role of aligning the liquid crystal in a predetermined direction. Specifically, the liquid crystal alignment film acts as a director in the alignment of liquid crystal molecules to take an appropriate direction when the liquid crystal moves by an electric field to form an image. In general, in order to obtain uniform brightness and high contrast ratio in a liquid crystal display device, it is essential to orient the liquid crystal uniformly.

  As a usual method of aligning liquid crystals, a polymer film such as polyimide is coated on a substrate such as glass, and a rubbing method in which this surface is rubbed in a certain direction using fibers such as nylon or polyester is known. It was used. However, the rubbing method may generate fine dust and electrical discharge (ESD) when the fibrous material and the polymer film rub, which may cause serious problems in the manufacture of the liquid crystal panel.

  In order to solve the problem of the rubbing method by friction, a UV alignment process is recently used. The UV alignment step is a photo alignment method of inducing anisotropy (anisotropy) in a polymer film by light irradiation and using this to align liquid crystals. The UV alignment process can improve the CR and the viewing angle by the improvement of alignment uniformity and the pretilt angle characteristic (̃0 degrees).

  However, the UV alignment step can replace the rubbing step with a non-contact alignment method, but requires an additional cleaning step.

  Conventionally, in the case of a washing step generally used after the UV alignment step, mainly water or a lower alcohol such as ethanol or IPA is used as a cleaning agent. However, when water, ethanol, or IPA treatment is performed as a cleaning agent, there is a problem that non-uniformity occurs in the liquid crystal alignment film, and the characteristics of the liquid crystal alignment film are greatly damaged.

  Therefore, after the UV alignment process, it is necessary to develop a new cleaning agent capable of preventing deterioration of the properties of the liquid crystal alignment film, and in particular, solving the problem of non-uniformity of the liquid crystal alignment film, and a cleaning method using the same.

  The object of the present invention is to improve the anisotropy of the liquid crystal alignment film obtained by the UV light alignment method through the cleaning of the polymer surface, and also to suppress the nonuniformity generated during the treatment process. And a method for producing a liquid crystal alignment film using the same.

  Another object of the present invention is to provide a liquid crystal display device including the liquid crystal alignment film according to the above method.

  According to one embodiment of the present invention, a liquid crystal alignment comprising tetrahydrofurfuryl alcohol or methyl 2-hydroxyisobutyrate, containing polyimide or a precursor of polyimide, and used for cleaning a UV-aligned liquid crystal alignment film A membrane cleaner composition is provided.

  The detergent composition is selected from the group consisting of an alkylene glycol compound having a viscosity of 10 cP or less and a boiling point of at least 150 ° C. and a polar solvent having a viscosity of 5 cP or less and a boiling point of at least 100 ° C. It may further comprise one or more of the compounds listed above.

  The detergent composition is a group consisting of a) 100% by weight of tetrahydrofurfuryl alcohol or methyl 2-hydroxyisobutyrate, or b) from 1 to 99% by weight of a) compound 1; and an alkylene glycol compound and a polar solvent And 0.1 to 99% by weight of one or more selected compounds.

  The detergent composition may further comprise 1 to 70% by weight of deionized water.

In the present invention, the step of coating a substrate with a liquid crystal aligning agent containing at least one polymer selected from the group consisting of a polyimide and a precursor of a polyimide and baking it to form a polyimide film;
Irradiating the substrate on which the polyimide film is formed with polarized radiation to perform a UV alignment process;
Cleaning the polymer surface with the substrate on which the UV alignment process is completed using a cleaning composition; and drying the cleaned substrate.
The detergent composition comprises tetrahydrofurfuryl alcohol or methyl 2-hydroxyisobutyrate.
The present invention provides a method for producing a liquid crystal alignment film, wherein an ionic by-product including a UV decomposition product of the polyimide film is cleaned and removed from the polymer surface of the polyimide film by a cleaning composition in the cleaning step.

  The detergent composition is selected from the group consisting of an alkylene glycol compound having a viscosity of 10 cP or less and a boiling point of at least 150 ° C. and a polar solvent having a viscosity of 5 cP or less and a boiling point of at least 100 ° C. It may further comprise one or more of the compounds listed above.

  Preferably, the detergent composition comprises 100% by weight of a compound selected from the group consisting of a) tetrahydrofurfuryl alcohol, and methyl 2-hydroxyisobutyrate, or b) 0.1 to 99% by weight of a) compound And 1 to 99% by weight of one or more compounds selected from the group consisting of an alkylene glycol compound and a polar solvent.

  The detergent composition may further comprise 1 to 70% by weight of deionized water.

  The alkylene glycol compound used in the cleaning agent composition is diethylene glycol terbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene It may be one or more selected from the group consisting of glycol monobutyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate.

  The polar solvent used for the cleaning composition is ethyl lactate, butyl lactate, hydroxy acid ester, N-methyl pyrrolidone, N-ethyl pyrrolidone, N-methyl formamide, 1,3-dimethyl-2-imidazolidinone, dimethyl It may be one or more selected from the group consisting of sulfoxide, dimethylacetamide, dimethylformamide, and tetramethylene sulfone.

  In the forming of the polyimide film, the baking process may include a soft or hard baking process.

［化学式２］

（前記化学式１および２で、
Ｘ^１およびＸ^２は、それぞれ独立して、炭素数４から２０の炭化水素に由来する４価の有機基であるか、あるいは前記４価の有機基のうちの一つ以上のＨがハロゲンで置換されるかまたは一つ以上の−ＣＨ_２−が酸素原子が直接連結されないように−Ｏ−、−Ｓ−、−ＣＯ−または−ＳＯ−に代替された４価の有機基であり、
Ｒ^１からＲ^４は、それぞれ独立して、水素または炭素数１から１０のアルキル基であり、
Ｒ^５からＲ^７は、それぞれ独立して、ハロゲン、シアノ基、炭素数２から１０のアルケニル基、炭素数１から１０のアルキル基、アルコキシ基またはフルオロアルキル基であり、
Ｌ^１は、−Ｏ−、−Ｏ−ＣＨ_２−Ｏ−、−Ｏ−ＣＨ_２ＣＨ_２−Ｏ−または−Ｏ−ＣＨ_２ＣＨ_２ＣＨ_２−Ｏ−であり、
ｐ、ｑおよびｒは、それぞれ独立して、０から４の整数であり、
ｎは、１または２の整数である。） The polyimide precursor may include the repeating unit represented by the following Chemical Formula 1 and the repeating unit of the following Chemical Formula 2.
[Chemical formula 1]

[Chemical formula 2]

(In the above formulas 1 and 2,
X ¹ and X ² are each independently a tetravalent organic group derived from a hydrocarbon having 4 to 20 carbon atoms, or one or more of H in the tetravalent organic group are halogens A tetravalent organic group substituted or substituted by -O-, -S-, -CO- or -SO- such that one or more -CH ₂ -is not directly linked to an oxygen atom,
R ¹ to R ⁴ are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms,
R ⁵ to R ⁷ each independently represent a halogen, a cyano group, an alkenyl group having 2 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an alkoxy group or a fluoroalkyl group,
L ¹ is —O—, —O—CH ₂ —O—, —O—CH ₂ CH ₂ —O— or —O—CH ₂ CH ₂ CH ₂ —O—
p, q and r are each independently an integer of 0 to 4,
n is an integer of 1 or 2. )

  The polyimide precursor may have a weight average molecular weight of 1,000 to 200,000 g / mol.

  Also, in the step of performing the UV alignment process, the substrate on which the polyimide film is formed may be irradiated with ultraviolet light or visible light having a wavelength of 150 to 450 nm, and the alignment film may be irradiated with linearly polarized light in the vertical or inclined direction. .

  According to another embodiment of the present invention, there is provided a liquid crystal display device including the liquid crystal alignment film manufactured by the method described above.

  In the present invention, the polymer of the liquid crystal alignment film is used by using a cleaning agent composition containing a specific solvent such as tetrahydrofurfuryl alcohol etc. in the cleaning process included after UV alignment in the process of manufacturing the liquid crystal alignment film. Surface ionic impurities can be easily removed. Therefore, according to the present invention, the anisotropy of the liquid crystal alignment film can be enhanced, and the nonuniformity generated during the treatment process can be suppressed, and the impurities remaining on the alignment film can be effectively removed. In addition, the present invention includes a liquid crystal alignment film that exhibits not only high stability and reliability but also excellent alignment stability and electrical properties, and can maintain CR and viewing angle improvement effects by the UV alignment process. A liquid crystal display device can be provided.

The cleaning mechanism after UV alignment is briefly shown in the method of manufacturing a liquid crystal alignment film. It compares and shows the RDC result before and behind washing | cleaning of a liquid crystal aligning film. It is a SEM photograph result which shows the decomposition product removal rate after exposure of Comparative Example 1 and Examples 1 to 5, and the decomposition product removal rate after exposure to the initial thickness of the liquid crystal alignment film before cleaning is the removal rate of polyimide. The thickness is measured and shown.

  Hereinafter, the present invention will be described more specifically. The terms and words used in the specification and claims should not be construed as limited to the ordinary or lexical meanings, and the inventors only have to describe their invention in the best possible manner. It should be interpreted as meaning and concept conforming to the technical idea of the present invention based on the principle that the concept of terms can be properly defined.

  Also, as used herein in the specification of the present invention, the meaning of "comprising" embodies a particular property, area, integer, step, action, element and / or component, and other property, area, integer, step, action, It does not exclude the presence or addition of elements and / or components.

  According to a preferred embodiment of the present invention, a liquid crystal containing tetrahydrofurfuryl alcohol or methyl 2-hydroxyisobutyrate, containing polyimide or a precursor of polyimide, and used for cleaning a UV-aligned liquid crystal alignment film An alignment film cleaning composition is provided.

  In addition, according to another embodiment of the present invention, a liquid crystal aligning agent containing one or more polymers selected from the group consisting of polyimide and a precursor of polyimide is coated on a substrate and fired to form a polyimide film. Applying UV radiation to the substrate on which the polyimide film has been formed, and performing UV alignment process; cleaning the polymer surface with the substrate on which the UV alignment process is completed using a cleaning composition And drying the cleaned substrate, wherein the cleaning composition comprises tetrahydrofurfuryl alcohol or methyl 2-hydroxyisobutyrate, and in the cleaning step UV degradation of the polyimide film And the step of cleaning and removing ionic by-products including the substance from the polymer surface of the polyimide film with a detergent composition.

  Such a cleaning agent composition for a liquid crystal alignment film of the present invention and a method for producing a liquid crystal alignment film using the same will be described in more detail below.

  In the present invention, a solvent having a specific structure is used as a detergent composition in order to solve the problem of non-uniformity generated in the conventional liquid crystal alignment cleaning process after the UV alignment process in the liquid crystal alignment film manufacturing process.

  That is, in the present invention, a liquid crystal is obtained by applying polarized radiation to a polyimide film obtained by applying and baking a polyimide film or a polyimide precursor, and then performing a cleaning process using a cleaning agent containing a specific solvent. It was confirmed that the anisotropy of the alignment film increased. Further, in the present invention, since the problem of non-uniformity with respect to the liquid crystal alignment film can be eliminated compared to the case where water, ethanol, or IPA treatment used as a conventional cleaning agent is performed, the characteristics of the liquid crystal alignment film are maintained. Can. The specific alignment film cleaning composition of the present invention does not clean the surface of the inorganic film as in the prior art, but cleans the impurities present on the polymer surface after the alignment is completed. That is, although the conventional cleaning agents were all cleaned only with the inorganic film of the alignment film, the cleaning agent composition of the present invention is different from those generally used for cleaning semiconductor elements in the prior art. There is a feature used as a cleaning application.

  Such a method for producing a liquid crystal alignment film of the present invention comprises the steps of coating a liquid crystal alignment agent on a substrate and baking it to form a polyimide, UV alignment step, cleaning step and drying step of the substrate on which the polyimide film is formed. Including (Thermal baking). In addition, after completion of the drying step, a cell bonding step can be performed.

  Alignment is performed on the surface of the polyimide film through the UV alignment step to form a liquid crystal alignment film, but UV decomposition products are present on the surface of the alignment film, and impurities on the polymer surface of the alignment film are removed In order to do this, a cleaning process using a cleaning agent is performed.

  Further, the cleaning mechanism of the liquid crystal alignment film is as shown in FIG. Referring to FIG. 1, when UV is applied to the polyimide film, ionic byproducts are generated on the surface of the alignment film, and problems of AC and DC image sticking occur, so that it is necessary to clean the UV decomposition product.

  Therefore, in the present invention, a cleaning composition containing a specific cleaning component is used to effectively clean the UV decomposition product. Such a detergent composition of the present invention is characterized by containing, as a main component, a compound selected from the group consisting of tetrahydrofurfuryl alcohol and methyl 2-hydroxyisobutyrate.

  The substances exhibit the same level of cleaning effect as each other, but more preferably contain tetrahydrofurfuryl alcohol. The cleaning effect of the tetrahydrofurfuryl alcohol can be increased when the temperature is increased from 25 ° C. to 80 ° C. after a certain period of time (eg, 1 to 3 minutes).

In particular, tetrahydrofurfuryl alcohol (hereinafter referred to as THFA) of the following chemical formula 1 used in the present invention simultaneously has a hydrophilic group and a hydrophobic group in the structure, has a good affinity with water, and is mixed with a solvent Sex is also good. In addition, the stability of the solution is good because there is no reactivity between the amine and water.
[Chemical formula 1]

  Therefore, by using the above-mentioned THFA as a cleaning agent composition, the present invention can prevent the characteristic deterioration of the liquid crystal alignment film (that is, the photo alignment film) as compared with the conventional one. Therefore, in the present invention, after forming a liquid crystal alignment film on a substrate using polyimide or a precursor thereof, the above-mentioned specific solvent is used as a cleaning agent composition to remain on the polymer surface of the liquid crystal alignment film. Can easily be removed. By using the cleaning composition, the present invention can easily remove ionic impurities on the surface of the liquid crystal alignment film, can solve the image sticking (IS), and makes the alignment film excellent in uniformity. Can be maintained.

  In addition, the detergent composition of the present invention may be used alone in the entire composition, although a compound selected from the group consisting of a) the tetrahydrofurfuryl alcohol and methyl 2-hydroxyisobutyrate can be used alone. B) in the form of a mixture further comprising an addition solvent.

  The addition solvent is selected from the group consisting of an alkylene glycol compound having a viscosity of 10 cP or less and a boiling point of at least 150 ° C., and a polar solvent having a viscosity of 5 cP or less and a boiling point of at least 100 ° C. One or more may be included.

  As a preferable example, the detergent composition of the present invention is a mixture of THFA and an alkylene glycol compound; a mixture of THFA and a polar solvent; a mixture of THFA and deionized water; a mixture of THFA and an alkylene glycol compound and a polar solvent A combination of THFA and an alkylene glycol compound and deionized water; or a mixture of THFA and an alkylene glycol compound, a polar solvent and deionized water may be selectively included.

  Also, the detergent composition according to a preferred embodiment may comprise 100% by weight of a compound selected from the group consisting of tetrahydrofurfuryl alcohol and methyl 2-hydroxyisobutyrate based on the total weight of the composition .

  And, said detergent composition comprises 100% by weight of a compound selected from the group consisting of a) tetrahydrofurfuryl alcohol and methyl 2-hydroxyisobutyrate based on the total weight of the composition, or b) above a) And 1) to 99% by weight of one or more compounds selected from the group consisting of an alkylene glycol compound and a polar solvent. At this time, in the case of the b) mixture, it may be preferable to be 50% of tetrahydrofurfuryl alcohol in the component a) in consideration of the washing effect on the polymer surface. More preferably, said detergent composition comprises a) 100% by weight of a) tetrahydrofurfuryl alcohol or methyl 2-hydroxyisobutyrate, or b) said a) compound 1 to 99%, based on the total weight of the composition. And 0.1 to 99% by weight of at least one compound selected from the group consisting of an alkylene glycol compound and a polar solvent.

  In addition, the detergent composition may further comprise 1 to 70% by weight of deionized water.

  The detergent composition of the present invention is selected from the group consisting of a) 20 to 80% by weight of tetrahydrofurfuryl alcohol; and b) the above alkylene glycol compound and a polar solvent based on the total weight of the composition. 1 or more 20 to 80 weight%; may be included.

  And, according to another preferred embodiment, the detergent composition comprises a) 20 to 70% by weight of tetrahydrofurfuryl alcohol based on the total weight of the composition; b) the alkylene glycol compound and a polar solvent And c) 10 to 60% by weight of deionized water.

  The above alkylene glycol compounds include diethylene glycol terbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, ethylene glycol mono It may be one or more selected from the group consisting of ethyl ether, propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate.

  And the polar solvent is ethyl lactate, butyl lactate, hydroxy acid ester, N-methyl pyrrolidone, N-ethyl pyrrolidone, N-methyl formamide, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, dimethyl acetamide, It may be one or more selected from the group consisting of dimethylformamide and tetramethylene sulfone.

  Moreover, you may use the thing obtained by the general ion exchange resin method as deionized water used by this invention.

  At this time, as shown in FIG. 1, the present invention may further include a washing step of the polyimide film before UV alignment, if necessary, and the method is not limited, and methods well known in this field are used. May be

  In the present invention, the cleaning step is performed by immersing the substrate on which the liquid crystal alignment film is formed in the cleaning composition described above for a certain period of time or spraying the cleaning composition onto the substrate. It is also good. Specifically, the cleaning process may be performed by immersing the substrate on which the coating is formed at a temperature of about 25 ° C. for about 1 to 10 minutes.

  The immersing step may be performed at a temperature of about 25 to 30 ° C. for about 3 to about 30 minutes, and the detergency can be confirmed in the above step. Also, the immersion process may be performed at a temperature of about 25 to about 30 ° C. for about 10 hours to about 24 hours in order to confirm etching and reliability.

  Meanwhile, the method of manufacturing a liquid crystal alignment film according to the present invention may be formed through various methods known in the technical field to which the present invention belongs, except that a specific cleaning composition is used in the cleaning step.

  As a non-limiting example, the liquid crystal alignment film may be formed by irradiating a light after applying and baking a liquid crystal alignment agent described later on a substrate. At this time, the baking and the light irradiation may be performed simultaneously, or the light irradiation may be omitted.

  That is, as described above, the step of forming the polyimide is performed by coating a substrate with a liquid crystal aligning agent containing at least one polymer selected from the group consisting of polyimide and a precursor of the polyimide and baking it. be able to.

  In the forming of the polyimide film, the baking process may include a soft or hard baking process. However, the firing step of the present invention is not particularly limited because all general methods can be used. In addition, if necessary, all soft baking and hard baking steps may be performed.

  Specifically, the liquid crystal alignment agent described above is applied to a substrate on which a liquid crystal alignment film is to be formed. As the substrate, all various substrates used in the technical field to which the present invention belongs may be used, and as the coating method, all various methods known in the technical field to which the present invention belong may be adopted. Good. As a non-limiting example, the liquid crystal aligning agent may be applied through methods such as screen printing, offset printing, flexographic printing, inkjet, and the like.

  Thereafter, the coating film manufactured above is fired. The baking may be performed at about 50 ° C. to 300 ° C. by a heating means such as a hot plate, a hot air circulation furnace, an infrared furnace or the like. When a soft baking process is performed, it may be performed at a temperature within about 70 ° C. for 100 seconds to 5 minutes, and when a hard baking process is performed, it may be performed at a temperature within about 230 ° C. for 1000 seconds.

  Among the polymers contained in the liquid crystal aligning agent through the baking process, repeating units represented by Chemical Formulas 1 and 3 may be imidized. The polymer may have the imidization repeating unit represented by the chemical formula 2 and may exhibit a significantly improved imide conversion compared to the prior art.

After the firing step, the fired film produced above can be irradiated with light according to the desired alignment direction to impart liquid crystal alignment. That is, photoalignment is performed by anisotropically reacting the alignment film by irradiating the polarized radiation on the liquid crystal alignment film obtained using the polyimide or the precursor thereof. Accordingly, in the step of irradiating the polarized radiation, the liquid crystal alignment film may be irradiated with ultraviolet light or visible light having a wavelength of 150 to 450 nm, and light linearly polarized in the vertical or inclined direction may be irradiated to the alignment film. At the time of the said ultraviolet irradiation, an exposure amount may be about 0.25-1 J / cm < ² >.

  After the cleaning process is completed, drying the cleaned substrate may be performed by spin drying or oven drying at a temperature of about 230 ° C. for 1000 seconds, although the conditions are not limited.

  In addition, the cell bonding step may include a dummy cell bonding step and an IPC cell bonding step, and the method is not limited.

  On the other hand, in the present invention, in the step of forming the polyimide film, a liquid crystal aligning agent containing at least one polymer selected from the group consisting of polyimide and a precursor of polyimide is coated on a substrate and fired. can get.

  The composition of the liquid crystal alignment agent may be provided through various methods known in the art to which the present invention belongs.

  As a non-limiting example, the above-described polymer can be dissolved or dispersed in an organic solvent to provide a liquid crystal aligning agent.

  Specific examples of the organic solvent include N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinyl Pyrrolidone, dimethyl sulfoxide, tetramethylurea, pyridine, dimethyl sulfone, hexamethyl sulfoxide, γ-butyrolactone, 3-methoxy-N, N-dimethylpropanamide, 3-ethoxy-N, N-dimethylpropanamide, 3-butoxy- N, N-dimethylpropanamide, 1,3-dimethyl-imidazolidinone, ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate , Like diglyme and 4-hydroxy-4-methyl-2-pentanone. These may be used alone or in combination.

  The liquid crystal aligning agent may additionally contain other components in addition to the polyimide polymer and the organic solvent. As a non-limiting example, when the liquid crystal alignment agent is applied, the uniformity of film thickness and surface smoothness are improved, or the adhesion between the liquid crystal alignment film and the substrate is improved, or the dielectric of the liquid crystal alignment film is Additives may be additionally included which can change the rate or conductivity or increase the compactness of the liquid crystal alignment film. As such additives, various solvents, surfactants, silane compounds, dielectrics or crosslinkable compounds may be exemplified.

  In addition, the polymer structure of the polyimide or its precursor used to obtain the liquid crystal alignment agent is not particularly limited, and any polymer that can form a polyimide-based polymer film well known in this field can be used. It is usable.

  For example, an aromatic diamine compound having a functional group and an aromatic tetracarboxylic acid anhydride can be used. The polyimide film may also be manufactured to contain a repeating unit of polyamic acid.

  Moreover, if a preferable example of the said polyimide precursor is given by this invention, you may also include the repeating unit represented by following Chemical formula 1, and the repeating unit of following Chemical formula 2.

  The polyimide may be a polymer in which at least a part of the repeating units of the polyimide precursor is imidized.

［化学式２］

（前記化学式１および２で、
Ｘ^１およびＸ^２は、それぞれ独立して、炭素数４から２０の炭化水素に由来する４価の有機基であるか、あるいは前記４価の有機基のうちの一つ以上のＨがハロゲンで置換されるかまたは一つ以上の−ＣＨ_２−が酸素原子が直接連結されないように−Ｏ−、−Ｓ−、−ＣＯ−または−ＳＯ−に代替された４価の有機基であり、
Ｒ^１からＲ^４は、それぞれ独立して、水素または炭素数１から４のアルキル基であり、
Ｒ^５からＲ^７は、それぞれ独立して、ハロゲン、シアノ基、炭素数２から１０のアルケニル基、炭素数１から１０のアルキル基、アルコキシ基またはフルオロアルキル基であり、
Ｌ^１は、−Ｏ−、−Ｏ−ＣＨ_２−Ｏ−、−Ｏ−ＣＨ_２ＣＨ_２−Ｏ−または−Ｏ−ＣＨ_２ＣＨ_２ＣＨ_２−Ｏ−であり、
ｐ、ｑおよびｒは、それぞれ独立して、０から４の整数であり、
ｎは、１または２の整数である。） Preferably, the repeating unit of Formula 1 in the polyimide precursor may have a content of 50 to 95 mol%, and the repeating unit of Formula 2 may have a content of 5 to 50 mol%.
[Chemical formula 1]

[Chemical formula 2]

(In the above formulas 1 and 2,
X ¹ and X ² are each independently a tetravalent organic group derived from a hydrocarbon having 4 to 20 carbon atoms, or one or more of H in the tetravalent organic group are halogens A tetravalent organic group substituted or substituted by -O-, -S-, -CO- or -SO- such that one or more -CH ₂ -is not directly linked to an oxygen atom,
R ¹ to R ⁴ are each independently hydrogen or an alkyl group having 1 to 4 carbon atoms,
R ⁵ to R ⁷ each independently represent a halogen, a cyano group, an alkenyl group having 2 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an alkoxy group or a fluoroalkyl group,
L ¹ is —O—, —O—CH ₂ —O—, —O—CH ₂ CH ₂ —O— or —O—CH ₂ CH ₂ CH ₂ —O—
p, q and r are each independently an integer of 0 to 4,
n is an integer of 1 or 2. )

  For reference, unless otherwise specified herein, the following terms may be defined as follows:

  Hydrocarbons having 4 to 20 carbons are alkanes having 4 to 20 carbons, alkenes having 4 to 20 carbons, alkynes having 4 to 20 carbons, and cyclos having 4 to 20 carbons. An alkane (cycloalkane), a C4-C20 cycloalkene (cycloalkene), a C6-C20 arene (arene), or one or more of these cyclic hydrocarbons share two or more atoms Or a fused ring, or one or more of them may be a chemically bonded hydrocarbon. Specifically, as the hydrocarbon having 4 to 20 carbon atoms, n-butane, cyclobutane, 1-methylcyclobutane, 1,3-dimethylcyclobutane, 1,2,3,4-tetramethylcyclobutane, cyclopentane, cyclohexane, Cycloheptane, cyclooctane, cyclohexene, 1-methyl-3-ethylcyclohexene, bicyclohexyl, benzene, biphenyl, diphenylmethane, 2,2-diphenylpropane, 1-ethyl-1,2,3,4-tetrahydronaphthalene or 1,2 6- diphenyl hexane etc. can be illustrated.

  The alkyl group having 1 to 10 carbon atoms may be a linear, branched or cyclic alkyl group. Specifically, the alkyl group having 1 to 10 carbon atoms is a linear alkyl group having 1 to 10 carbon atoms; a linear alkyl group having 1 to 5 carbon atoms; a branched or cyclic alkyl group having 3 to 10 carbon atoms; Or a branched or cyclic alkyl group having 3 to 6 carbon atoms. More specifically, as the alkyl group having 1 to 10 carbon atoms, methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, n-pentyl group A group, an iso-pentyl group, a neo-pentyl group or a cyclohexyl group can be exemplified.

  The C 1 -C 10 alkoxy group may be a linear, branched or cyclic alkoxy group. Specifically, the alkoxy group having 1 to 10 carbon atoms is a linear alkoxy group having 1 to 10 carbon atoms; a linear alkoxy group having 1 to 5 carbon atoms; a branched or cyclic alkoxy group having 3 to 10 carbon atoms; Or a branched or cyclic alkoxy group having 3 to 6 carbon atoms. More specifically, examples of the alkoxy group having 1 to 10 carbon atoms include methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, iso-butoxy, tert-butoxy and n-pentoxy A group, an iso-pentoxy group, a neo-pentoxy group, a cyclohexoxy group etc. can be illustrated.

  The C 1 -C 10 fluoroalkyl group may be one in which one or more hydrogens of the C 1 -C 10 alkyl group are substituted with fluorine.

  The C 2-10 alkenyl group may be a linear, branched or cyclic alkenyl group. Specifically, the alkenyl group having 2 to 10 carbons is a linear alkenyl group having 2 to 10 carbons, a linear alkenyl group having 2 to 5 carbons, a branched alkenyl group having 3 to 10 carbons, and a carbon number It may be a branched alkenyl group of 3 to 6, a cyclic alkenyl group of 5 to 10 carbon atoms, or a cyclic alkenyl group of 6 to 8 carbon atoms. More specifically, examples of the alkenyl group having 2 to 10 carbon atoms include ethenyl group, prophenyl group, butenyl group, pentenyl group and cyclohexenyl group.

  The halogen may be fluorine (F), chlorine (Cl), bromine (Br) or iodine (I).

  A multivalent organic group derived from any compound means a residue in a form in which a plurality of hydrogen atoms bonded to any compound have been removed. As an example, a tetravalent organic group derived from cyclobutane means a residue in a form in which any four hydrogen atoms bonded to cyclobutane are removed.

は、シクロブタンの１、２、３および４番炭素に結合された水素原子４つが除去された形態の残基、つまり、シクロブタンに由来する４価の有機基のうちのいずれか一つを意味する。 In the present specification, the chemical formula means a residue in a form in which hydrogen at the site is removed. For example,

Means a residue in a form in which four hydrogen atoms bonded to carbons 1, 2, 3 and 4 of cyclobutane are removed, that is, any one of tetravalent organic groups derived from cyclobutane .

  Also, a polyimide precursor herein may mean a polyamic acid or an ester of a polyamic acid that can provide a polyimide under appropriate conditions.

  If it demonstrates more concretely, the repeating unit of said Chemical formula 1 may be a repeating unit produced | generated by making the diamine of linear form react with tetracarboxylic acid or its anhydride. The polyimide precursor according to an embodiment of the present invention can provide a liquid crystal alignment film having a liquid crystal alignment property and reliability significantly improved by including a repeating unit derived from a linear form diamine as represented by Formula 1 above. .

［化学式１−２］

［化学式１−３］

［化学式１−４］

［化学式１−５］

前記化学式１−１から１−５で、Ｘ^１、Ｒ^１、Ｒ^２、Ｒ^５およびｐの定義は化学式１の定義と同じである。 In addition, the repeating unit of Formula 1 may include a divalent organic group derived from a linear form of diamine. As a result, in the repeating unit of Formula 1, two amino groups may be attached to positions 1 and 4 (for example, Formula 1-1) or positions 1 and 3 (for example, Formula 1-2) of benzene, respectively. Or positions 3 and 3 of biphenyl (eg, chemical formula 1-3), positions 4 and 4 '(eg, chemical formula 1-4) or positions 3 and 4' (eg, chemical formula 1-5). Specific examples of such a repeating unit of Chemical Formula 1 may be structures as shown by Chemical Formulas 1-1 to 1-5 below.
[Chemical formula 1-1]

[Chemical formula 1-2]

[Chemical formula 1-3]

[Chemical formula 1-4]

[Chemical formula 1-5]

In Formulas 1-1 to 1-5, the definitions of X ¹ , R ¹ , R ² , R ^5, and p are the same as those of Formula 1.

  When the repeating unit of the chemical formula 1 is one or more repeating units of the chemical formulas 1-1 and 1-4, a polyimide precursor capable of realizing more stable liquid crystal alignment can be provided.

  On the other hand, the repeating unit of the chemical formula 2 can impart liquid crystal orientation to the polyimide manufactured from the polyimide precursor according to the embodiment even with light irradiation with a small exposure amount. By this, the orientation stability and reliability by the repeating unit of Formula 1 can be realized without undesired side reactions. That is, the liquid crystal alignment film having excellent general physical properties of the photo alignment film can be provided while realizing excellent alignment stability like a rubbing alignment film by the repeating unit of the above-mentioned chemical formula 1 and chemical formula 2.

  In order to realize the excellent various physical properties of the photo alignment film while realizing the excellent alignment stability and reliability as described above, the polyimide precursor according to the one embodiment is a repeating unit of the formula 1 with respect to the entire repeating unit. The unit may be contained at a content of 50 to 95 mol%, and the repeating unit of the formula 2 may be contained at a content of 5 to 50 mol%.

The polyimide precursor according to one embodiment may be prepared from tetracarboxylic acids or anhydrides thereof known in the art to which the present invention belongs, and therefore, X ¹ and X ² are repeating units of Formula 1 and Formula 2, respectively. As mentioned above, various tetravalent organic groups may be used.

前記化学式３で、
Ｒ^８からＲ^１１は、それぞれ独立して、水素または炭素数１から６のアルキル基であり、
Ｌ^２は、−Ｏ−、−Ｓ−、−ＣＯ−、−ＳＯ−、−Ｃ（ＣＦ_３）_２−または−ＣＯＯ−ＣＨ_２ＣＨ_２−ＯＣＯ−である。 As one example, X ¹ and X ² may be each independently a tetravalent organic group described in the following Chemical Formula 3.
[Chemical formula 3]

In the above formula 3,
R ⁸ to R ¹¹ each independently represent hydrogen or an alkyl group having 1 to 6 carbon atoms,
L ² is —O—, —S—, —CO—, —SO—, —C (CF ₃ ) ₂ — or —COO—CH ₂ CH ₂ —OCO—.

前記化学式３−１で、Ｒ^８からＲ^１１の定義は化学式３の定義と同じである。 At least a part of the X ¹ and X ² may be a tetravalent organic group represented by the following chemical formula 3-1 in the chemical formula 3.
[Chemical formula 3-1]

In Formula 3-1, the definitions of R ⁸ to R ¹¹ are the same as those of Formula 3.

As described above, the repeating unit of Chemical Formula 1 in which X ¹ is a tetravalent organic group of Chemical Formula 3-1 or the repeating unit of Chemical Formula ^{2 in} which X ² is a tetravalent organic group of Chemical Formula 3-1 is simple by light irradiation. Thus, the liquid crystal alignment can be easily realized. In order to secure such an effect more effectively, the repeating unit of the chemical formula 1 wherein X ¹ is a tetravalent organic group of the chemical formula 3-1 and X ² is a tetravalent organic group of the chemical formula 3-1 The total of the repeating units of Formula 2 may be adjusted to 60 to 100 mol% with respect to the entire repeating unit.

The polyimide precursor according to the one embodiment may be a polyamic acid or a polyamic acid ester. When the polyimide precursor is a polyamic acid, R ¹ to R ⁴ may be hydrogen in the repeating units of the chemical formulas 1 and 2, and when it is a polyamic acid ester, at least a portion of R ¹ to R ⁴ may be It may be an alkyl group having 1 to 10 carbon atoms.

On the other hand, the phenylene group derived from diamine may be substituted with R ⁵ , R ⁶ or R ⁷ in the repeating units of the above formulas 1 and 2. And, hydrogen may be bonded to the carbon not substituted with R ⁵ , R ⁶ or R ⁷ in the phenylene group. In the repeating units represented by a plurality of chemical formulas 1, each R ⁵ may be the same as or different from each other, and in the repeating units similarly represented by a plurality of chemical formulas 2 each R ⁶ and R ⁷ are the same as each other But it may be different.

  The polyimide precursor according to one embodiment may be manufactured to have an appropriate degree of polymerization depending on the desired physical properties. As one example, the polyimide precursor may be prepared to have a weight average molecular weight of 1,000 to 200,000 g / mol. It is possible to provide a liquid crystal alignment film exhibiting good general physical properties within such a range.

  Meanwhile, according to another embodiment of the present invention, there is provided a liquid crystal display device including the liquid crystal alignment film manufactured by the method described above.

  That is, after cleaning the substrate on which the liquid crystal alignment film is formed by the method described above, the present invention can manufacture a liquid crystal alignment film containing a liquid crystal alignment agent, and such a liquid crystal alignment film may be used to manufacture a liquid crystal display element. It can be applied to

  The fact that the liquid crystal alignment film contains the liquid crystal alignment agent as described above means that the liquid crystal alignment film contains the liquid crystal alignment agent itself or that the liquid crystal alignment film contains the product obtained through the chemical reaction of the liquid crystal alignment agent. means.

  The liquid crystal alignment film may be introduced to the liquid crystal cell by a known method, and the liquid crystal cell may be similarly introduced to the liquid crystal display element by a known method. The liquid crystal alignment film can realize excellent stability as well as excellent physical properties because it uses the cleaning method exhibiting the excellent cleaning power described above. Thus, a liquid crystal display device capable of showing high reliability can be provided.

  Also, the liquid crystal display device referred to in the present invention may be manufactured by a method well known in the field except for the liquid crystal alignment film provided by the above-mentioned method, and thus the specific description will be omitted.

  Hereinafter, the operation and effects of the invention will be more specifically described through specific examples of the invention. However, this is only presented as an illustration of the invention, and this does not limit the scope of the invention's rights in any way.

  <Comparative Examples 1 to 12 and Examples 1 to 34>

Production of Liquid Crystal Alignment Agent and Liquid Crystal Cell (1) Production of Liquid Crystal Alignment Agent Solid content 5% by weight of polyimide polymer (Mw: 23 000 to 27000) in a mixed solvent having a weight ratio of NMP to n-butoxyethanol of 8: 2. Melted at a ratio of Then, the resulting solution was pressure-filtered with a filter having a pore size of 0.2 μm of a poly (tetrafluoroethylene) material to produce a liquid crystal aligning agent.

(2) Production of Liquid Crystal Cell A liquid crystal cell was produced by the following method using the liquid crystal alignment agent produced above.

  A comb-like IPS (in-plane switching) mode ITO electrode pattern with a thickness of 60 nm, an electrode width of 3 μm and an inter-electrode spacing of 6 μm is formed on a rectangular glass substrate having a size of 2.5 cm × 2.7 cm. A liquid crystal aligning agent was applied to each of the substrate (lower plate) and the glass substrate (upper plate) having no electrode pattern by using a spin coating method.

  Next, the substrate coated with the liquid crystal alignment agent is placed on a hot plate at about 70 ° C. and dried for 1000 seconds, and then hard baked in an oven at about 230 ° C. for 1000 seconds to form a 0.1 μm thick polyimide film I got

In order to align the coating film thus obtained, exposure of ultraviolet light of 254 nm at 0.25 to 1 J / cm ² using an exposure device in which a linear polarizer is attached to each coating film of the upper and lower plates Irradiated by volume.

  Thereafter, the components in Tables 1 to 7 were mixed to produce the cleaning compositions of Comparative Examples 1 to 12 and Examples 1 to 34. Thereafter, the substrate having the coating film formed on the cleaning composition of each of the examples and the comparative examples was immersed for about 5 minutes at a temperature of 25 ° C. to proceed the substrate cleaning process.

  When the washing process was completed, it was dried in a 230 ° oven for 1000 seconds.

  Thereafter, a sealing agent impregnated with a ball spacer having a size of 3 μm was applied to the periphery of the upper plate of the substrate except for the liquid crystal injection port. Then, after aligning the alignment films formed on the upper and lower plates so that they face each other and align the alignment directions, the upper and lower plates are bonded to cure the sealing agent to produce a vacant cell. did. Then, liquid crystal was injected into the vacant cell to manufacture an IPS mode liquid crystal cell.

  Test example

<Characteristics evaluation of liquid crystal alignment film>
The anisotropy, the film uniformity, the black level, and the AC residual image fluctuation rate were measured by the following method with respect to the liquid crystal alignment film washed using the cleaning agent composition used in Examples and Comparative Examples. The results are shown in Tables 1 to 6.

(1) Evaluation of Anisotropy The anisotropy of the liquid crystal alignment film was evaluated by the AxoStep method.
(Evaluation criteria)
1: Decreased anisotropy by 10% or more after washing 2: Decreased anisotropy within 10% after washing 3: Level of same anisotropy value as before washing 4: Difference after washing The anisotropy value rises within 10% 5: The anisotropy value after washing rises by 10% or more

(2) Evaluation of film uniformity The film uniformity of the liquid crystal alignment film was evaluated by the AFM method.
(Evaluation criteria)
1: Increase in surface roughness value after cleaning by 10% or more 2: Increase in surface roughness value after cleaning within 10% 3: Level with same surface roughness value as before cleaning 4: Surface after cleaning Roughness value decreases within 10% 5: Surface roughness value after cleaning decreases by 10% or more

(3) Evaluation of Black Level The black level of the liquid crystal alignment film was evaluated by the PR-880 method.
(Evaluation criteria)
1: Black value after washing decreased by 10% or more 2: Black value after washing increased by 10% or more 3: Level of black value identical to that before washing 4: Black value after washing decreased within 10% 5: Black value after washing decreases by 10% or more

注）
ＴＨＦＡ：Ｔｅｔｒｅｈｙｄｒｏｆｕｒｆｕｒｙｌ ａｌｃｏｈｏｌ
ＩＰＡ：Ｉｓｏｐｒｏｐｙｌ ａｌｃｏｈｏｌ
ＭＤＧ：Ｄｉｅｔｈｙｌｅｎｅｇｌｙｃｏｌ ｍｏｎｏｍｅｔｈｙｌ ｅｔｈｅｒ （ｍｅｔｈｙｌ ｃａｒｂｉｔｏｌ）
ＭＧ：Ｅｔｈｙｌｅｎｅｇｌｙｃｏｌ ｍｏｎｏｍｅｔｈｙｌ ｅｔｈｅｒ
ＥＤＧ：Ｄｉｅｔｈｙｌｅｎｅｇｌｙｃｏｌ ｍｏｎｏｅｔｈｙｌ ｅｔｈｅｒ （ｅｔｈｙｌ ｃａｒｂｉｔｏｌ）
ＥＧ：Ｅｔｈｙｌｅｎｅｇｌｙｃｏｌ ｍｏｎｏｅｔｈｙｌ ｅｔｈｅｒ
ＢＤＧ：Ｄｉｅｔｈｙｌｅｎｅｇｌｙｃｏｌ ｍｏｎｏｂｕｔｙｌ ｅｔｈｅｒ （ｂｕｔｙｌ ｃａｒｂｉｔｏｌ）
ＢＧ：Ｅｔｈｙｌｅｎｅｇｌｙｃｏｌ ｍｏｎｏｂｕｔｙｌ ｅｔｈｅｒ
ＮＭＰ：Ｎ−ｍｅｔｈｙｌ ｐｙｒｒｏｌｉｄｏｎｅ
ＮＥＰ：Ｎ−ｅｔｈｙｌ ｐｙｒｒｏｌｉｄｏｎｅ
ＨＢＭ：ｍｅｔｈｙｌ， ２−ｈｙｄｒｏｘｙｉｓｏｂｕｔｙｒａｔｅ
ＩＰ−ＥＬ：Ｉｓｏｐｒｏｐｙｌ ｌａｃｔａｔｅ
ＢＬ：Ｂｕｔｙｌ ｌａｃｔａｔｅ

(4) Evaluation of AC residual image fluctuation rate After applying an AC 12 V voltage at 60 degrees and 24 hours, the AC residual image fluctuation rate of the liquid crystal alignment film was evaluated by the PR-800 method.
(Evaluation criteria)
1: Level of change in AC residual image fluctuation rate after cleaning is 100% or more Level of AC residual image fluctuation rate change after cleaning is 30% or more 3: Level of AC residual image fluctuation rate is the same as that before cleaning (20 %Rate of change)
4: Level of change in AC residual image variation rate within 10% after washing 5: Level of change in AC residual image variation rate after wash 5%

note)
THFA: Tetrehydrofurfuryl alcohol
IPA: Isopropyl alcohol
MDG: Diethyleneglycol monomethyl ether (methyl carbitol)
MG: Ethyleneglycol monomethyl ether
EDG: Diethyleneglycol monoethyl ether (ethyl carbitol)
EG: Ethyleneglycol monoethyl ether
BDG: Diethyleneglycol monobutyl ether (butyl carbitol)
BG: Ethyleneglycol monobutyl ether
NMP: N-methyl pyrrolidone
NEP: N-ethyl pyrrolidone
HBM: methyl, 2-hydroxyisobutyrate
IP-EL: Isopropyl lactate
BL: Butyl lactate

  Through the results of Tables 1 to 7, Examples 1 to 34 of the present invention showed superior results in anisotropy, film uniformity, Black level, and AC residual image fluctuation rate as compared with Comparative Examples 1 to 12 in general. It was confirmed. In particular, as can be seen from the results in Table 1, in the case of Comparative Example 1 containing only EL, the cleaning power is lower than in the examples containing the specific solvent of the present invention (in particular, THFA or HBM). Was bad. In addition, when the alcohol solvent, the alkylene glycol solvent or the polar solvent of Comparative Examples 2 to 12 is contained alone, the physical properties of the liquid crystal alignment film were generally lower than those of Examples.

(5) RDC evaluation (residual DC voltage, residual DC)
The RDC before and after cleaning of the liquid crystal alignment film in Example 1 was measured, and the results are shown in FIG.

  As can be seen from FIG. 2, the residual voltage characteristics were improved by using the cleaning agent composition of Example 1 of the present invention.

(6) Measurement of decomposition product removal rate (the faster the decomposition rate, the better the detergency)
For Comparative Example 1 and Examples 1 to 5, the decomposition product removal rate after exposure was measured in the usual way through the polyimide removal rate (the film decreased from the initial level), and the results are shown in Table 8 and FIG. The That is, FIG. 3 is a SEM photograph result which shows the decomposition product removal rate after exposure of Comparative Example 1 and Examples 1 to 5, and the decomposition product removal rate after exposure with respect to the initial thickness of the liquid crystal alignment film before cleaning. The thickness is measured at a removal rate of polyimide.

  From the results of Table 8 and FIG. 3, it was confirmed that the cleaning power is excellent because the decomposition rate is faster than in the case where the present invention contains the ethyl lactate of Comparative Example 1 in the practice of the present invention.

(7) Measurement of RDC With respect to Comparative Example 1 and Examples 1 to 5, RDC was measured by a usual method, and the results are shown in Table 9.

  It is confirmed through Table 9 that the residual DC value is smaller than in the case where Examples 1 to 5 of the present invention contain only ethyl lactate of Comparative Example 1, so that the cleaning ability is excellent.

Preferably, the detergent composition comprises 100% by weight of a compound selected from the group consisting of a) tetrahydrofurfuryl alcohol and methyl 2-hydroxyisobutyrate, or b) 99% by weight of a) compound 1 ; And 0.1 to 99% by weight of one or more compounds selected from the group consisting of alkylene glycol compounds and polar solvents.

Among the polymers contained in the liquid crystal aligning agent through the baking process, repeating units represented by Chemical Formulas 1 and 2 may be imidized. The polymer may have the imidization repeating unit represented by the chemical formula 2 and may exhibit a significantly improved imide conversion compared to the prior art.

［化学式２］

（前記化学式１および２で、
Ｘ^１およびＸ^２は、それぞれ独立して、炭素数４から２０の炭化水素に由来する４価の有機基であるか、あるいは前記４価の有機基のうちの一つ以上のＨがハロゲンで置換されるかまたは一つ以上の−ＣＨ_２−が酸素原子が直接連結されないように−Ｏ−、−Ｓ−、−ＣＯ−または−ＳＯ−に代替された４価の有機基であり、
Ｒ^１からＲ^４は、それぞれ独立して、水素または炭素数１から１０のアルキル基であり、
Ｒ^５からＲ^７は、それぞれ独立して、ハロゲン、シアノ基、炭素数２から１０のアルケニル基、炭素数１から１０のアルキル基、アルコキシ基またはフルオロアルキル基であり、
Ｌ^１は、−Ｏ−、−Ｏ−ＣＨ_２−Ｏ−、−Ｏ−ＣＨ_２ＣＨ_２−Ｏ−または−Ｏ−ＣＨ_２ＣＨ_２ＣＨ_２−Ｏ−であり、
ｐ、ｑおよびｒは、それぞれ独立して、０から４の整数であり、
ｎは、１または２の整数である。） Preferably, the repeating unit of Formula 1 in the polyimide precursor may have a content of 50 to 95 mol%, and the repeating unit of Formula 2 may have a content of 5 to 50 mol%.
[Chemical formula 1]

[Chemical formula 2]

(In the above formulas 1 and 2,
X ¹ and X ² are each independently a tetravalent organic group derived from a hydrocarbon having 4 to 20 carbon atoms, or one or more of H in the tetravalent organic group are halogens A tetravalent organic group substituted or substituted by -O-, -S-, -CO- or -SO- such that one or more -CH ₂ -is not directly linked to an oxygen atom,
R ¹ to R ⁴ are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms,
R ⁵ to R ⁷ each independently represent a halogen, a cyano group, an alkenyl group having 2 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an alkoxy group or a fluoroalkyl group,
L ¹ is —O—, —O—CH ₂ —O—, —O—CH ₂ CH ₂ —O— or —O—CH ₂ CH ₂ CH ₂ —O—
p, q and r are each independently an integer of 0 to 4,
n is an integer of 1 or 2. )

(3) Evaluation of Black Level The black level of the liquid crystal alignment film was evaluated by the PR-880 method.
(Evaluation criteria)
1: Black value after washing increased by 10% or more 2: Black value after washing increased by 10% or more 3: Level of black value identical to that before washing 4: Black value after washing decreased within 10% 5: Black value after washing decreases by 10% or more

Claims (19)

Containing tetrahydrofurfuryl alcohol or methyl 2-hydroxyisobutyrate
A cleaning composition for a liquid crystal alignment film, which comprises a polyimide or a precursor of a polyimide and is used for cleaning a UV-aligned liquid crystal alignment film.   The detergent composition is selected from the group consisting of an alkylene glycol compound having a viscosity of 10 cP or less and a boiling point of at least 150 ° C. and a polar solvent having a viscosity of 5 cP or less and a boiling point of at least 100 ° C. The cleaning agent composition for liquid crystal aligning films of Claim 1 which further contains the said 1 or more types of compound. The detergent composition is
a) 100% by weight of tetrahydrofurfuryl alcohol or methyl 2-hydroxyisobutyrate, or b) one or more selected from the group consisting of a) compound 1 to 99% by weight of the compound a) and an alkylene glycol compound and a polar solvent The composition for a liquid crystal alignment film according to claim 1, comprising 0.1 to 99% by weight of the compound of   The cleaning composition according to claim 1, wherein the cleaning composition further comprises 1 to 70% by weight of deionized water.   The above alkylene glycol compounds include diethylene glycol terbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, ethylene glycol mono The cleaning composition for a liquid crystal alignment film according to claim 2, which is at least one selected from the group consisting of ethyl ether, propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate.   The polar solvent is ethyl lactate, butyl lactate, hydroxy acid ester, N-methyl pyrrolidone, N-ethyl pyrrolidone, N-methyl formamide, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, dimethyl acetamide, dimethylformamide And the cleaning agent composition for liquid crystal aligning films of Claim 2 which is 1 or more types selected from the group which consists of tetramethylene sulfone. The liquid crystal alignment film is
Coating a liquid crystal aligning agent containing at least one polymer selected from the group consisting of polyimide and a precursor of polyimide on a substrate and baking it to form a polyimide film; and the polyimide film is formed The composition for cleaning a liquid crystal alignment film according to claim 1, obtained by a method comprising the steps of: irradiating a substrate with polarized radiation to perform a UV alignment step. The cleaning composition for a liquid crystal alignment film according to claim 7, wherein the polyimide precursor comprises a repeating unit represented by the following chemical formula 1 and a repeating unit of the following chemical formula 2.
[Chemical formula 1]

[Chemical formula 2]

(In the above formulas 1 and 2,
X ¹ and X ² are each independently a tetravalent organic group derived from a hydrocarbon having 4 to 20 carbon atoms, or one or more of H in the tetravalent organic group are halogens A tetravalent organic group substituted or substituted by -O-, -S-, -CO- or -SO- such that one or more -CH ₂ -is not directly linked to an oxygen atom,
R ¹ to R ⁴ are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms,
R ⁵ to R ⁷ each independently represent a halogen, a cyano group, an alkenyl group having 2 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an alkoxy group or a fluoroalkyl group,
L ¹ is —O—, —O—CH ₂ —O—, —O—CH ₂ CH ₂ —O— or —O—CH ₂ CH ₂ CH ₂ —O—
p, q and r are each independently an integer of 0 to 4,
n is an integer of 1 or 2. ) Coating a substrate with a liquid crystal aligning agent containing at least one polymer selected from the group consisting of polyimide and a precursor of polyimide on a substrate and firing to form a polyimide film;
Irradiating the substrate on which the polyimide film is formed with polarized radiation to perform a UV alignment process;
Cleaning the polymer surface with the substrate on which the UV alignment process is completed using a cleaning composition; and drying the cleaned substrate.
The detergent composition comprises tetrahydrofurfuryl alcohol or methyl 2-hydroxyisobutyrate.
A method for producing a liquid crystal alignment film, wherein in the cleaning step, ionic by-products including UV decomposition products of the polyimide film are cleaned and removed from the polymer surface of the polyimide film by a cleaning composition.   The detergent composition is selected from the group consisting of an alkylene glycol compound having a viscosity of 10 cP or less and a boiling point of at least 150 ° C. and a polar solvent having a viscosity of 5 cP or less and a boiling point of at least 100 ° C. The manufacturing method of the liquid crystal aligning film of Claim 9 which further contains said 1 or more types of compounds. The detergent composition is
a) 100% by weight of tetrahydrofurfuryl alcohol or methyl 2-hydroxyisobutyrate, or b) one or more selected from the group consisting of a) compound 1 to 99% by weight of the compound a) and an alkylene glycol compound and a polar solvent A method for producing a liquid crystal alignment film according to claim 9, comprising 0.1 to 99% by weight of the compound of   The method for producing a liquid crystal alignment film according to claim 9, wherein the detergent composition further comprises 1 to 70% by weight of deionized water.   The above alkylene glycol compounds include diethylene glycol terbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, ethylene glycol mono The manufacturing method of the liquid crystal aligning film of Claim 10 which is 1 or more types selected from the group which consists of ethyl ether, a propylene glycol monomethyl ether, and a propylene glycol monomethyl ether acetate.   The polar solvent is ethyl lactate, butyl lactate, hydroxy acid ester, N-methyl pyrrolidone, N-ethyl pyrrolidone, N-methyl formamide, 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, dimethyl acetamide, dimethylformamide , And the manufacturing method of the liquid crystal aligning film of Claim 10 which is 1 or more types selected from the group which consists of tetramethylene sulfone.   The method for producing a liquid crystal alignment film according to claim 9, wherein in the forming of the polyimide film, the baking process includes a soft or hard baking process. The method for producing a liquid crystal alignment film according to claim 9, wherein the polyimide precursor contains a repeating unit represented by the following chemical formula 1 and a repeating unit of the following chemical formula 2.
[Chemical formula 1]

[Chemical formula 2]

(In the above formulas 1 and 2,
X ¹ and X ² are each independently a tetravalent organic group derived from a hydrocarbon having 4 to 20 carbon atoms, or one or more of H in the tetravalent organic group are halogens A tetravalent organic group substituted or substituted by -O-, -S-, -CO- or -SO- such that one or more -CH ₂ -is not directly linked to an oxygen atom,
R ¹ to R ⁴ are each independently hydrogen or an alkyl group having 1 to 10 carbon atoms,
R ⁵ to R ⁷ each independently represent a halogen, a cyano group, an alkenyl group having 2 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an alkoxy group or a fluoroalkyl group,
L ¹ is —O—, —O—CH ₂ —O—, —O—CH ₂ CH ₂ —O— or —O—CH ₂ CH ₂ CH ₂ —O—
p, q and r are each independently an integer of 0 to 4,
n is an integer of 1 or 2. )   The method for producing a liquid crystal alignment film according to claim 9, wherein the polyimide precursor has a weight average molecular weight of 1,000 to 200,000 g / mol.   The step of performing the UV alignment process may include irradiating the substrate having the polyimide film formed thereon with visible light from ultraviolet light having a wavelength of 150 to 450 nm and irradiating the alignment film with light linearly polarized in the vertical or inclined direction. The manufacturing method of the liquid crystal aligning film as described in-.   The liquid crystal display element containing the liquid crystal aligning film manufactured by the method of Claim 9.

Images